The Complete Guide to Arctic Cat Clutch Kits: Performance, Maintenance & Upgrades​

The single most effective modification you can make to your Arctic Cat snowmobile to improve its overall performance, throttle response, and rideability is installing the correct clutch kit. A clutch kit fine-tunes the engagement, shifting, and back-shifting behavior of your primary and secondary clutches to perfectly match your specific engine, riding style, altitude, and track setup. Whether you ride a mountain sled, a trail cruiser, or a high-performance crossover, understanding and optimizing your Arctic Cat clutch kit is foundational to unlocking your machine's true potential. This guide will explain everything from basic clutch function and maintenance to advanced tuning and aftermarket kit selection, providing you with the practical knowledge to make informed decisions.

​Understanding the Arctic Cat CVT Clutch System​

Your Arctic Cat snowmobile does not have a traditional transmission with gears. Instead, it uses a Continuously Variable Transmission (CVT) system, comprised of two main clutches connected by a drive belt. This system is brilliantly simple, entirely mechanical, and highly tunable.

1. ​The Primary Clutch (Drive Clutch):​​ This clutch is bolted directly to the end of the engine's crankshaft. Its job is to convert the engine's rotational power into belt drive force. Inside, it uses weighted arms called ​flyweights​ and a spring. As engine RPM increases, centrifugal force pushes the flyweights outward. This action squeezes the clutch sheaves together, pinching the belt and driving it outward toward the clutch's outer diameter. This is analogous to shifting a bicycle into a higher gear.

2. ​The Secondary Clutch (Driven Clutch):​​ This clutch is mounted on the shaft that turns the track's drive axle. Its primary function is to provide the opposite reaction. It uses a powerful spring to keep its sheaves clamped on the belt. As belt speed and force from the primary increase, the belt forces the secondary sheaves apart, allowing the belt to ride deeper into the clutch, effectively creating a lower gear ratio for increased torque.

The magic of the CVT is that this "shifting" happens seamlessly and continuously, always seeking the optimal gear ratio to keep the engine operating in its peak power band (RPM) for any given load and speed.

​Why Clutch Kits Are Essential for Arctic Cat Sleds​

Factory clutch calibration is a compromise. Arctic Cat engineers must set up the clutches to perform adequately for an average rider, at an average altitude, with stock components, across all temperature and snow conditions. This "one-size-fits-most" approach leaves significant performance on the table. A proper clutch kit addresses the specific variables that affect performance:

• ​Altitude Changes:​​ Air density decreases with altitude, reducing engine horsepower. A kit calibrated for high mountains will have different weights and springs to maintain target RPM with less engine power.
• ​Riding Style & Terrain:​​ Aggressive mountain boondocking requires instant back-shifting for quick tree-to-tree maneuvers. Trail riding prioritizes smooth, consistent shifting and top-end speed. A kit is tailored for these behaviors.
• ​Engine Modifications:​​ Adding a performance exhaust, a fuel controller, or a big-bore kit increases horsepower. The stock clutch cannot manage this extra power efficiently and will often "over-shift" or slip, requiring a kit to harness it.
• ​Track & Gearing Changes:​​ Installing a longer, heavier lug track or changing the chaincase gearing alters the load on the drivetrain. The clutch must be re-tuned to accommodate this new load profile.
• ​Correcting Factory Imprecision:​​ Even within stock parameters, clutch components can have manufacturing variances. A kit ensures precise, repeatable performance.

​Core Components of an Arctic Cat Clutch Kit​

A typical aftermarket clutch kit will include some or all of the following components. Understanding each part's role is key to tuning.

• ​Primary Clutch Spring:​​ This spring determines the force required to start closing the primary clutch (engagement RPM) and influences the rate of upshift. ​A stiffer spring raises engagement RPM and can create a more aggressive, quicker-shifting feel.​​ A softer spring lowers engagement.
• ​Flyweights (Weights):​​ These are the heart of tuning. Heavier weights will cause the clutch to upshift (shift out) earlier at a given RPM, which can lower overall engine RPM. Lighter weights allow the engine to rev higher before upshifting. The ​weight's profile or "curve"​​ is equally important; a weight designed for a quick, aggressive shift will have a different center of gravity than one designed for a smooth, linear shift.
• ​Secondary Clutch Spring:​​ This spring controls the clamping force on the belt in the secondary clutch. It governs back-shifting (how quickly the sled downshifts when you let off the throttle) and affects how well the belt grips under heavy load. ​A helix with a different angle or a different secondary spring rate is a common kit component to improve back-shifting performance.​​
• ​Helix:​​ Mounted inside the secondary clutch, this cam-shaped plate dictates how the secondary sheaves move in relation to each other. The ​angle of the helix​ (e.g., 36-42 degrees) controls the shift ratio. A multi-angle helix (e.g., 36/40) provides a progressive shift, starting aggressively and finishing more gradually for better top speed.
• ​Calibration Instructions:​​ A quality kit provides specific instructions for your model, altitude, and modifications. This is the "recipe" that makes the components work together harmoniously.

​Step-by-Step: Diagnosing Common Arctic Cat Clutch Problems​

Before buying a kit, diagnose your current setup. Many performance issues are clutch-related.

1. ​Sled Won't Reach Proper Peak RPM (Bogs/Flattens Out):​​

   • ​Likely Cause:​​ Clutch is "upshifting" too quickly or too much. The engine is being loaded down.
   • ​Check:​​ Primary weights may be too heavy. Primary spring may be too stiff. Belt may be worn or glazed.

2. ​Engine Over-Revving (RPMs Too High, Especially on Takeoff):​​

   • ​Likely Cause:​​ Clutch is not upshifting enough ("stuck in a low gear").
   • ​Check:​​ Primary weights may be too light. Primary spring may be too weak or broken. Belt may be incorrect width or severely worn.

3. ​Poor or Laggy Back-Shifting (Sled Stays in a High Gear After Letting Off):​​

   • ​Likely Cause:​​ Secondary clutch is not closing quickly enough when load decreases.
   • ​Check:​​ Secondary spring may be too weak or heat-faded. Helix may be gummed with old grease. Bushings may be worn, causing binding.

4. ​Belt Squeal or Burning Smell:​​

   • ​Likely Cause:​​ Belt slippage due to insufficient clamping force or contamination.
   • ​Check:​​ Secondary spring may be too weak. Sheaves may be dirty or glazed. Belt may be contaminated with oil or grease. Alignment between clutches may be off.

5. ​Erratic or "Bumpy" Shifting:​​

   • ​Likely Cause:​​ Worn or damaged components causing inconsistent operation.
   • ​Check:​​ Primary clutch rollers and bushings for flat spots or wear. Spider bushing in the primary. Secondary clutch bushings. All pivots points for rust or lack of lubrication.

​Essential Maintenance: The Foundation of Good Clutch Performance​

No high-performance kit will work correctly on a neglected clutch. Regular maintenance is non-negotiable.

​Primary Clutch Maintenance:​​

• ​Disassembly & Cleaning:​​ Annually, the primary clutch should be completely disassembled, cleaned with a non-petroleum-based solvent (like brake cleaner), and inspected.
• ​Rollers and Pins:​​ Inspect the rollers on the flyweight arms for flat spots or cracks. Check the pivot pins for wear. Replace as a set if any are damaged.
• ​Spring:​​ Check the primary spring for signs of splaying, cracking, or loss of tension. Compare its free length to the service manual specification.
• ​Bushings:​​ Check the movable sheave bushing and spider bushing for excessive play. Wobble here destroys alignment and causes vibration.
• ​Lubrication:​​ Lightly lubricate the weight pins and pivots with a specific ​dry-film clutch lubricant. Never use grease or oil, as it will attract dust and cause sticking.

​Secondary Clutch Maintenance:​​

• ​Disassembly & Cleaning:​​ Similarly, disassemble the secondary to clean the helix, spring, and sheaves.
• ​Helix & Sheave Ramps:​​ Clean off all old, hardened grease from the helix and the corresponding ramps on the movable sheave. Polish any minor burrs with emery cloth.
• ​Lubrication:​​ Apply a ​thin layer of high-quality clutch-specific grease​ (like a moly grease) to the helix ramps and the sheave contact points. Too much grease will be flung onto the belt.
• ​Spring:​​ Inspect the secondary spring for heat discoloration (blueing) or cracking. A heat-faded spring has lost its tension.
• ​Bushing:​​ Check the sheave bushing for wear.

​Belt Care & Alignment:​​

• ​Alignment:​​ Use a straightedge or laser alignment tool to ensure both clutches are perfectly in line. Misalignment is a major cause of belt wear and heat.
• ​Belt Inspection:​​ Look for cracks, frayed cords, glazing (shiny, hardened surface), and excessive wear. Measure the belt width; a worn, narrow belt will sit too deep in the clutches and perform poorly.
• ​Belt Break-in:​​ A new belt should be run at varying, moderate speeds for the first 20-50 miles to seat it properly before hard acceleration.

​Choosing the Right Aftermarket Clutch Kit for Your Arctic Cat​

The market offers kits from tuners who specialize in Arctic Cat performance. Research is crucial.

1. ​Altitude-Specific Kits:​​ Brands like ​Speedwerx, Dalton Industries, and EPI (Excellent Performance Inc.)​​ offer kits specifically labeled for 0-3000ft, 3000-6000ft, 6000-9000ft, etc. This is the most critical filter when choosing.
2. ​Application-Specific Kits:​​ Kits are designed for ​Mountain, Trail/Cross-Over, or Hillclimb/Drag​ applications. A mountain kit prioritizes instant throttle response and explosive back-shifting. A trail kit focuses on smooth, efficient shifting and top-speed optimization.
3. ​Stage Kits for Mods:​​ If you've added performance parts, look for "Stage" kits (e.g., Stage 1 for intake/exhaust, Stage 2 for head/pipes, etc.). These are calibrated for the expected horsepower gains.
4. ​Complete vs. Calibration Kits:​​ A complete kit includes springs and weights (and sometimes a helix). A calibration kit may only include weights and instructions, assuming you will use a recommended aftermarket spring.
5. ​Reputation and Support:​​ Choose a manufacturer known for Arctic Cat expertise. Good technical support is invaluable if you have questions during installation or fine-tuning.

​Installation Guide: How to Install an Arctic Cat Clutch Kit​

​SAFETY FIRST: The primary clutch is under extreme spring pressure. Always use a certified clutch compression tool (like from EPI or OTC) to disassemble and reassemble the primary clutch. Never attempt to pry it apart.​​

​Tools Needed:​​ Clutch compression tool, clutch holder, torque wrench, socket set, allen keys, dry-film lube, clutch grease, shop towels, brake cleaner.

​Part 1: Removing the Clutches.​​

1. Disconnect the battery.
2. Remove the belt by prying the secondary clutch sheaves apart with a belt tool.
3. ​Hold the primary clutch​ using a clutch holding tool or a strap wrench. Remove the center bolt. The clutch may slide off easily or require a puller.
4. Remove the secondary clutch by loosening the set screw(s) on the collar and sliding it off the shaft.

​Part 2: Disassembling & Installing the Primary Kit.​​

1. Place the primary clutch in the compression tool and compress it until the snap ring is exposed. Remove the snap ring carefully.
2. Slowly release the tool tension. The spring will expand, and you can now remove the movable sheave, spring, and weight assembly.
3. Clean all parts thoroughly. Install the new flyweights onto the spider arms, lubricating the pins with dry-film lube.
4. Place the new primary spring into the fixed sheave (note its orientation—which end is coiled tighter).
5. Reassemble the movable sheave and spider/weight assembly. Compress the clutch in the tool and re-install the snap ring, ensuring it is fully seated in its groove.
6. Torque the center bolt to the manufacturer's specification (typically 45-65 ft-lbs for an Arctic Cat, but ALWAYS verify in your service manual).

​Part 3: Disassembling & Installing the Secondary Kit.​​

1. Secure the secondary clutch in a vise with protective jaws.
2. Using the appropriate tool, twist the movable sheave against spring pressure until the helix pins align with removal holes. Retain the spring tension.
3. Remove the helix, then carefully release and remove the spring.
4. Clean the helix, sheaves, and inside of the spring. Apply a thin layer of clutch grease to the helix ramps.
5. If the kit includes a new spring or helix, install them now. Reassemble in the reverse order, ensuring the helix is clocked correctly according to the kit instructions.

​Part 4: Reinstallation & Alignment.​​

1. Slide the secondary clutch onto the shaft, align the key, and tighten the set screw(s).
2. Install the primary clutch onto the crankshaft. Use a small amount of anti-seize on the shaft splines. Hold the clutch and torque the center bolt to spec.
3. Check clutch alignment with a straightedge. Adjust if necessary by adding or removing shims behind the secondary clutch.
4. Install a new or properly broken-in belt.
5. Reconnect the battery.

​Fine-Tuning and Final Testing​

Your clutch kit will be 90-95% dialed from the instructions. Fine-tuning adjusts for your exact sled and conditions.

• ​The Goal:​​ Achieve and maintain your engine's ​target peak RPM​ (as specified by the kit manufacturer or engine builder) during a full-throttle, long-track run on hard pack.
• ​Too Low RPM:​​ If RPM is consistently 200-300 below target, your clutch is upshifting too much. ​Solution:​​ Install slightly lighter flyweights or a slightly softer primary spring (if the kit allows for spring changes).
• ​Too High RPM:​​ If RPM is consistently above target, your clutch is not upshifting enough. ​Solution:​​ Install slightly heavier flyweights or a slightly stiffer primary spring.
• ​Test Procedure:​​ Make only one change at a time. After a change, go for a test ride under consistent snow conditions. Use a reliable tachometer. Note the engagement RPM and the peak RPM during a sustained pull.

By following this comprehensive guide—from understanding the basics, performing critical maintenance, selecting the right kit, installing it correctly, to final fine-tuning—you will transform the performance and reliability of your Arctic Cat snowmobile. The clutch system is the direct link between your engine's power and the track on the snow; optimizing it is the most rewarding mechanical improvement you can undertake.